In $$\triangle$$ABC, AD bisects $$\angle$$A and intersects BC at D. If BC = a, AC = b and AB = c, then BD = ?

A

$$\frac{ca}{a + b}$$

B

$$\frac{bc}{c + a}$$

C

$$\frac{ac}{b + c}$$

D

$$\frac{ab}{b + c}$$